Despite numerous reports of the design and delivery of novel nanomedicines such as dendrimer-drug conjugates, only relatively few studies have examined their therapeutic potential at the molecular level. In particular, there are currently no convenient and quick approaches to identify specific subsets of intracellular targets of drug candidates. The long-term goals of this proposal are to apply proteomic approaches to identify intracellular drug targets and to develop novel therapeutic agents based on nanoparticles. The objective of this application is to use dendrimer-protein tyrosine phosphatase (PTP) inhibitor conjugates as a model system to establish a proteomic platform that efficiently and reproducibly characterizes the specificity and activity of these nanomedicines. Our rationale is that dendrimers functionalized with PTP inhibitors will not only efficiently deliver these small drug candidates intracellularly, but will also provide a powerful proteomic tool to probe their therapeutic targets in living cells. The proposed research will capitalize on our ability to create multi-functional groups on the surface of dendrimers such that they can achieve efficient intracellular delivery for specific targeting and then can be readily isolated for subsequent proteomic analyses. Guided by strong preliminary data, this much needed technology will be achieved by pursuing three specific aims: 1) to synthesize multi-functionalized dendrimers containing an immobilized PTP inhibitor;2) to identify PTP targets in cancer cell homogenates;and 3) to identify PTP protein targets in intact cancer cells in culture. Under aim 1, an already proven synthetic route will be applied to the preparation of multifunctionalized dendrimer agents. Under aims 2 and 3, the activity and specificity of these dendrimer agents will be examined in vitro and in living cells, respectively. This project is innovative as the proposed studies will be among the first to combine the use of dendrimers as drug carriers (nanomedicines) and potential therapeutic agents with proteomics to identify therapeutic targets. It will capitalize on a powerful technique to directly identify therapeutic targets in living cells. Once the utility of this strategy is established, it is highly likely that it can be expanded to the characterization of a large number of nanomedicines based on dendrimers and other nanoparticles. The fully developed tool will provide detailed knowledge at the molecular level on precisely how nanomedicines react and interact with their intracellular targets. The research will be of significance because it expands the important role of proteomics and its contribution to a new field and provides a powerful tool needed for drug discovery that will allow us to evaluate the actions of nanomedicines at the molecular level. In addition, functionalized dendrimers and other related nanoparticles will provide unique materials for use as novel proteomics reagents. PUBLIC HEALTH RELEVANCE: This application is proposing noteworthy studies that have the potential applicability to identifying therapeutic targets in living systems in high throughput, as well as to developing new generation medicine, in particular nanomedicine. The proposed research has strong relevance to general public health, since the technology can be potentially expanded to any disease and drug discovery area.